[feat] a CONTRIBUTING.md

[davidgtl]

Description 📝

To contribute effectively, it would be useful to know:

• What is the general file structure/architecture and how various pieces fit together (e.g. engine_fragment, three.js, BIM Tiles, etc.)
• What is the develoment cycle for a feature/bugfix which includes:
  • how to clone & setup a local environment e.g. github's guide
  • how to build & test the code against the examples (e.g. via a local python3 -m http.server 8000)
  • formatting & code style
  • commit message format e.g. conventional commits

The entrypoint for all this pieces of info is expected to be a CONTRIBUTING.md file

Suggested solution 💡

A detailed CONTRIBUTING.md file in the project root containing the above information

There is some information about getting started e.g. https://docs.thatopen.com/components/getting-started, but it's not geared towards working on this codebase

Alternative ⛕

No response

Additional context ☝️

No response

Validations ✅

• [X] Read the docs.
• [X] Check that there isn't already an issue that requests the same feature to avoid creating a duplicate.

[HoyosJuan]

Thanks a lot @davidgtl! We will keep this in mind to do it asap.

[agviegas]

We have created a contributing page in our docs. I think it includes all the points you mentioned, but let us know otherwise. Cheers!